Planar waveguide apparatus having a plurality of diffractive optical elements
View Patent ↗A waveguide apparatus includes a planar waveguide and at least one optical diffraction element (DOE) that provides a plurality of optical paths between an exterior and interior of the planar waveguide. A phase profile of the DOE may combine a linear diffraction grating with a circular lens, to shape a wave front and produce beams with desired focus. Waveguide apparatus may be assembled to create multiple focal planes. The DOE may have a low diffraction efficiency, and planar waveguides may be transparent when viewed normally, allowing passage of light from an ambient environment (e.g., real world) useful in AR systems. Light may be returned for temporally sequentially passes through the planar waveguide. The DOE(s) may be fixed or may have dynamically adjustable characteristics. An optical coupler system may couple images to the waveguide apparatus from a projector, for instance a biaxially scanning cantilevered optical fiber tip.
1. A waveguide apparatus, comprising:
a planar waveguide having an at least partially transparent optical element comprising a first end, a second end, a first face, and a second face, wherein the planar waveguide is configured to permit light beams emitted by or reflected from physical objects that are located on a far side of the planar waveguide relative to a viewer to reach at least one eye of the viewer; and
a plurality of diffractive optical elements comprising two dynamic diffractive optical elements and operatively coupled to the planar waveguide, wherein
the two dynamic diffractive optical elements have different diffractive lens aspects such that when each of the two dynamic diffractive elements is alternatively switched on, the each of the two dynamic diffractive elements focuses light to a different focus distance,
the first and second ends of the planar waveguide are opposed to each other along a length of the planar waveguide,
the first and the second faces of the planar waveguide form an at least partially internally reflective optical path along a portion of the length of the planar waveguide, and
the plurality of diffractive optical elements are configured to interrupt the at least partially internally reflective optical path to provide a respective plurality of optical paths between an exterior and an interior of the planar waveguide via the first face thereof at respective positions along the portion of the length of the planar waveguide.
2. The waveguide apparatus of claim 1 , wherein a diffractive optical element of the plurality is integral with the planar waveguide.
3. The waveguide apparatus of claim 1 , wherein a diffractive optical element of the plurality is disposed between the first face and the second face of the planar waveguide.
4. The waveguide apparatus of claim 1 , wherein a diffractive optical element of the plurality is disposed at one of the first face or the second face of the planar waveguide.
5. The waveguide apparatus of claim 1 , wherein a diffractive optical element of the plurality is a Bragg grating.
6. The waveguide apparatus of claim 1 , wherein one or more diffractive optical elements of the plurality of diffractive optical elements combine a linear diffraction function and a radially circular lens function.
7. The waveguide apparatus of claim 1 , wherein a diffractive optical element of the plurality has a phase profile that is a combination of a linear diffraction grating and a radially symmetric lens.
8. The waveguide apparatus of claim 1 , wherein each diffractive optical element of the plurality is generally parallel to a field-of-view of the planar waveguide.
9. The waveguide apparatus of claim 1 , wherein a diffractive optical element of the plurality is a dynamic diffractive optical element.
10. The waveguide apparatus of claim 1 , wherein the two diffractive optical elements are configured to be switched on simultaneously, such that their diffractive effects are combined.
11. The waveguide apparatus of claim 1 , wherein the two diffractive optical elements of the plurality have different phase maps, such that, when each of the two diffractive elements are alternatively switched on, each of the two diffractive elements directs the light to a different spatial position.
12. The waveguide apparatus of claim 1 , wherein the two diffractive optical elements of the plurality have different linear grating aspects, such that, when each of the two diffractive elements are alternatively switched on, the two diffractive elements produce respective sub-images that are laterally displaced relative to each other.
13. The waveguide apparatus of claim 1 , wherein the diffractive optical elements of the plurality are each dynamic diffractive optical elements, and wherein the diffractive optical elements are configured to be sequentially switched on and off.
14. The waveguide apparatus of claim 1 , wherein the plurality of diffractive optical elements are arranged relative to the planar waveguide to manipulate input light beams of digital imagery into exit light beams based in part or in whole upon one or more designed focus levels to project the digital imagery to the at least one eye of the viewer.
15. The waveguide apparatus of claim 14 , wherein the digital imagery includes a digital image of a virtual object, and the digital image of the virtual object is presented together with the light beams emitted by or reflected from the physical objects to the at least one eye of the viewer.
16. The waveguide apparatus of claim 14 , further comprising:
a light source operatively coupled to the planar waveguide to transmit the input light beams of the digital imagery into the planar waveguide, wherein
at least some of the plurality of diffractive optical elements are configured to combine a first phase function with a second phase function, and
the first phase function and the second phase function are used to manipulate the input light beams
the first phase function or the second phase function is configured to expand exit pupil of the exit light beams;
the second phase function is configured to shape light wavefront of at least a part of the input light beams and to steer the at least the part of the input light beams at an angle that matches a designed focus level of the one or more designed focus levels.
17. The waveguide apparatus of claim 14 , further comprising:
an optical fiber;
one or more light sources optically coupled to a proximal end of the optical fiber;
a piezoelectric device operatively coupled to a distal end of the optical fiber and including or associated with a plurality of electrodes; and
drive electronics operatively driving the plurality of electrodes to deform the piezoelectric device.
18. The waveguide apparatus of claim 17 , wherein the drive electronics is configured to drive the piezoelectric device in a plurality of axes independently with simulated resonant vibration so that a portion of the optical fiber on the distal end is scanned along the plurality of axes.
19. A waveguide apparatus, comprising:
a planar waveguide having an at least partially transparent optical element comprising a first end, a second end, a first face, and a second face, wherein the planar waveguide is configured to permit light beams emitted by or reflected from physical objects that are located on a far side of the planar waveguide relative to a viewer to reach at least one eye of the viewer; and
a plurality of diffractive optical elements comprising two dynamic diffractive optical elements and operatively coupled to the planar waveguide, wherein
the two dynamic diffractive optical elements have different linear grating aspects, such that, when each of the two dynamic diffractive elements is alternatively switched on, the two dynamic diffractive elements produce respective sub-images that are laterally displaced relative to each other,
the first and second ends of the planar waveguide are opposed to each other along a length of the planar waveguide,
the first and the second faces of the planar waveguide form an at least partially internally reflective optical path along a portion of the length of the planar waveguide, and
the plurality of diffractive optical elements are configured to interrupt the at least partially internally reflective optical path to provide a respective plurality of optical paths between an exterior and an interior of the planar waveguide via the first face thereof at respective positions along the portion of the length of the planar waveguide.
20. The waveguide apparatus of claim 19 , wherein the two dynamic diffractive optical elements have different diffractive lens aspects, such that, when each of the two dynamic diffractive elements is alternatively switched on, each of the two dynamic diffractive elements focuses light to a different focus distance.